XO/PR on sloped roofs (ventilated, hybrid or warm) provides the most efficient U-values with minimal intrusion into valuable living space. The roof construction is a critical element in the building fabric and is an area at high risk of heat loss. Using XO/PR will reduce heat loss while also delivering excellent thermal bridging details. Warm Roof Construction is a particularly effective way of insulating complex roofs. Insulating above – or above and between – the roof timbers ensures that the structure is kept at or near the internal environment conditions, reducing thermal stress and condensation risk.